Owing to their low dimensionality, two-dimensional semiconductors, such as monolayer molybdenum disulfide, have a range of properties that make them valuable in the development of nanoelectronics. For example, the electronic bandgap of these semiconductors is not an intrinsic physical parameter and can be engineered by manipulating the dielectric environment around the monolayer. Here we show that this dielectric-dependent electronic bandgap can be used to engineer a lateral heterojunction within a homogeneous MoS2 monolayer. We visualize the heterostructure with Kelvin probe force microscopy and examine its influence on electrical transport experimentally and theoretically. We observe a lateral heterojunction with an approximately 90 meV band offset due to the differing degrees of bandgap renormalization of monolayer MoS2 when it is placed on a substrate in which one segment is made from an amorphous fluoropolymer (Cytop) and another segment is made of hexagonal boron nitride. This heterostructure leads to a diode-like electrical transport with a strong asymmetric behaviour.
Subscribe to Journal
Get full journal access for 1 year
only $8.25 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Rent or Buy article
Get time limited or full article access on ReadCube.
All prices are NET prices.
The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request
Wang, Q. H., Kalantar-Zadeh, K., Kis, A., Coleman, J. N. & Strano, M. S. Electronics and optoelectronics of two-dimensional transition metal dichalcogenides. Nat. Nanotechnol. 7, 699–712 (2012).
Butler, S. Z. et al. Progress, challenges, and opportunities in two-dimensional materials beyond graphene. ACS Nano 7, 2898–2926 (2013).
Xia, F., Wang, H., Xiao, D., Dubey, M. & Ramasubramaniam, A. Two-dimensional material nanophotonics. Nat. Photon. 8, 899–907 (2014).
Radisavljevic, B. & Kis, A. Mobility engineering and a metal–insulator transition in monolayer MoS2. Nat. Mater. 12, 815–820 (2013).
Mak, K. F., McGill, K. L., Park, J. & McEuen, P. L. The valley Hall effect in MoS2 transistors. Science 344, 1489–1492 (2014).
Cui, X. et al. Multi-terminal transport measurements of MoS2 using a van der Waals heterostructure device platform. Nat. Nanotechnol. 10, 534–540 (2015).
Fiori, G. et al. Electronics based on two-dimensional materials. Nat. Nanotechnol. 9, 768 (2014).
Jariwala, D., Sangwan, V. K., Lauhon, L. J., Marks, T. J. & Hersam, M. C. Emerging device applications for semiconducting two-dimensional transition metal dichalcogenides. ACS Nano 8, 1102–1120 (2014).
Chhowalla, M., Jena, D. & Zhang, H. Two-dimensional semiconductors for transistors. Nat. Rev. Mater. 1, 16052 (2016).
Qiu, D. Y., da Jornada, F. H. & Louie, S. G. Optical spectrum of MoS2: many-body effects and diversity of exciton states. Phys. Rev. Lett. 111, 216805 (2013).
Chernikov, A. et al. Exciton binding energy and nonhydrogenic Rydberg series in monolayer WS2. Phys. Rev. Lett. 113, 076802 (2014).
Qiu, D. Y., da Jornada, F. H. & Louie, S. G. Screening and many-body effects in two-dimensional crystals: Monolayer MoS2. Phys. Rev. B 93, 235435 (2016).
Ugeda, M. M. et al. Giant bandgap renormalization and excitonic effects in a monolayer transition metal dichalcogenide semiconductor. Nat. Mater. 13, 1091–1095 (2014).
Ye, Z. et al. Probing excitonic dark states in single-layer tungsten disulphide. Nature 513, 214–218 (2014).
Zhang, C., Johnson, A., Hsu, C.-L., Li, L.-J. & Shih, C.-K. Direct imaging of band profile in single layer MoS2 on graphite: Quasiparticle energy gap, metallic edge states, and edge band bending. Nano. Lett. 14, 2443–2447 (2014).
Zhu, B., Chen, X. & Cui, X. Exciton binding energy of monolayer WS2. Sci. Rep. 5, 9218 (2015).
Hill, H. M. et al. Observation of excitonic Rydberg states in monolayer MoS2 and WS2 by photoluminescence excitation spectroscopy. Nano. Lett. 15, 2992–2997 (2015).
Zhang, Y. et al. Electronic structure, surface doping, and optical response in epitaxial WSe2 thin films. Nano. Lett. 16, 2485–2491 (2016).
Komsa, H.-P. & Krasheninnikov, A. V. Effects of confinement and environment on the electronic structure and exciton binding energy of MoS2 from first principles. Phys. Rev. B 86, 241201 (2012).
Stier, A. V., Wilson, N. P., Clark, G., Xu, X. & Crooker, S. A. Probing the influence of dielectric environment on excitons in monolayer WSe2: Insight from high magnetic fields. Nano. Lett. 16, 7054–7060 (2016).
Ryou, J., Kim, Y.-S., Kc, S. & Cho, K. Monolayer MoS2 bandgap modulation by dielectric environments and tunable bandgap transistors. Sci. Rep. 6, 29184 (2016).
Raja, A. et al. Coulomb engineering of the bandgap and excitons in two-dimensional materials. Nat. Commun. 8, 15251 (2017).
Cho, Y. & Berkelbach, T. C. Environmentally sensitive theory of electronic and optical transitions in atomically-thin semiconductors. Phys. Rev. B 97, 041409(R) (2018).
Bradley, A. J. et al. Probing the role of interlayer coupling and Coulomb interactions on electronic structure in few-layer MoSe2 nanostructures. Nano. Lett. 15, 2594–2599 (2015).
Andersen, K., Latini, S. & Thygesen, K. S. Dielectric genome of van der Waals heterostructures. Nano. Lett. 15, 4616–4621 (2015).
Latini, S., Olsen, T. & Thygesen, K. S. Excitons in van der Waals heterostructures: the important role of dielectric screening. Phys. Rev. B 92, 245123 (2015).
Olsen, T., Latini, S., Rasmussen, F. & Thygesen, K. S. Simple screened hydrogen model of excitons in two-dimensional materials. Phys. Rev. Lett. 116, 056401 (2016).
Nonnenmacher, M., O’Boyle, M. P. & Wickramasinghe, H. K. Kelvin probe force microscopy. Appl. Phys. Lett. 58, 2921–2923 (1991).
Melitz, W., Shen, J., Kummel, A. C. & Lee, S. Kelvin probe force microscopy and its application. Surf. Sci. Rep. 66, 1–27 (2011).
Tosun, M. et al. MoS2 heterojunctions by thickness modulation. Sci. Rep. 5, 10990 (2015).
Forsythe, C. et al. Band structure engineering of 2D materials using patterned dielectric superlattices. Nat. Nanotechnol. 13, 566–571 (2018).
Li, L. et al. Direct observation of the layer-dependent electronic structure in phosphorene. Nat. Nanotechnol. 12, 21–25 (2016).
Qiu, D. Y., da Jornada, F. H. & Louie, S. G. Environmental screening effects in 2D materials: renormalization of the bandgap, electronic structure, and optical spectra of few-layer black phosphorus. Nano. Lett. 17, 4706–4712 (2017).
Geick, R., Perry, C. H. & Rupprecht, G. Normal modes in hexagonal boron nitride. Phys. Rev. 146, 543–547 (1966).
Liu, B. et al. Engineering bandgaps of monolayer MoS2 and WS2 on fluoropolymer substrates by electrostatically tuned many-body effects. Adv. Mater. 28, 6457–6464 (2016).
Dean, C. R. et al. Boron nitride substrates for high-quality graphene electronics. Nat. Nanotechnol. 5, 722–726 (2010).
Sze, S. M. & Ng, K. K. Physics of Semiconductor Devices (Wiley, Hoboken, 2007).
Sedra, A. S. & Smith, K. C. Microelectronic Circuits 5th edn (Oxford Univ. Press, New York, 2004).
Hybertsen, M. S. & Louie, S. G. Electron correlation in semiconductors and insulators: band gaps and quasiparticle energies. Phys. Rev. B 34, 5390–5413 (1986).
Deslippe, J. et al. BerkeleyGW: A massively parallel computer package for the calculation of the quasiparticle and optical properties of materials and nanostructures. Comp. Phys. Comm. 183, 1269–1289 (2012).
da Jornada, F. H., Qiu, D. Y. & Louie, S. G. Nonuniform sampling schemes of the Brillouin zone for many-electron perturbation-theory calculations in reduced dimensionality. Phys. Rev. B 95, 035109 (2017).
Jin, C. et al. Imaging of pure spin–valley diffusion current in WS2–WSe2 heterostructures. Science 360, 893–896 (2018).
Alam, K. & Lake, R. K. Monolayer MoS2 transistors beyond the technology road map. IEEE Trans. Elect. Dev. 59, 3250–3254 (2012).
Desai, S. B. et al. MoS2 transistors with 1-nanometer gate lengths. Science 354, 99–102 (2016).
Das, S., Chen, H.-Y., Penumatcha, A. V. & Appenzeller, J. High performance multilayer MoS2 transistors with scandium contacts. Nano. Lett. 13, 100–105 (2013).
Giannazzo, F., Fisichella, G., Piazza, A., Agnello, S. & Roccaforte, F. Nanoscale inhomogeneity of the Schottky barrier and resistivity in MoS2 multilayers. Phys. Rev. B 92, 081307 (2015).
Cui, X. et al. Low-temperature Ohmic contact to monolayer MoS2 by van der Waals bonded Co/h-BN electrodes. Nano. Lett. 17, 4781–4786 (2017).
Liu, Y. et al. Approaching the Schottky–Mott limit in van der Waals metal–semiconductor junctions. Nature 557, 696–700 (2018).
Maier, G. Low dielectric constant polymers for microelectronics. Prog. Polym. Sci. 26, 3–65 (2001).
Stoppa, M. & Chiolerio, A. Wearable electronics and smart textiles: a critical review. Sensors 14, 11957 (2014).
Levendorf, M. P. et al. Graphene and boron nitride lateral heterostructures for atomically thin circuitry. Nature 488, 627–632 (2012).
Liu, Z. et al. In-plane heterostructures of graphene and hexagonal boron nitride with controlled domain sizes. Nat. Nanotechnol. 8, 119–124 (2013).
Castellanos-Gomez, A. et al. Deterministic transfer of two-dimensional materials by all-dry viscoelastic stamping. 2D Mater. 1, 011002 (2014).
Lee, G.-H. et al. Flexible and transparent MoS2 field-effect transistors on hexagonal boron nitride–graphene heterostructures. ACS Nano 7, 7931–7936 (2013).
We thank M. Asta, J. Yao and S. Kahn for helpful discussions. This work was primarily supported by the Center for Computational Study of Excited State Phenomena in Energy Materials, which is funded by the US Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division under Contract No. DE-AC02-05CH11231, as part of the Computational Materials Sciences Program. The device fabrication is supported by the National Science Foundation EFRI Program (EFMA-1542741). This research used resources of the National Energy Research Scientific Computing Center (NERSC), a DOE Office of Science User Facility supported by the Office of Science of the US Department of Energy under Contract No. DE-AC02-05CH11231, and the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by National Science Foundation grant number ACI-1548562. H.K. was supported by the Deutsche Forschungsgemeinschaft (KL 2961/1-1). C.S.O. acknowledges support from the Singapore National Research Foundation (Clean Energy) PhD Scholarship. R.K. was supported by the JSPS Overseas Research Fellowship Program. S.T. acknowledges support from a NSF DMR 1552220 NSF CAREER award. Growth of hexagonal boron nitride crystals was supported by the Elemental Strategy Initiative conducted by the MEXT, Japan and a Grant-in-Aid for Scientific Research on Innovative Areas ‘Science of Atomic Layers’ from JSPS.
The authors declare no competing interests.
Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
About this article
Cite this article
Utama, M.I.B., Kleemann, H., Zhao, W. et al. A dielectric-defined lateral heterojunction in a monolayer semiconductor. Nat Electron 2, 60–65 (2019). https://doi.org/10.1038/s41928-019-0207-4
Materials Today (2020)
CMOS compatible novel integration solution for broad range tunable photodetection using phase-change material based heterostructures
Scientific Reports (2020)